MOF derived in-situ synthesized MnS three-dimensional nano array electrode material, preparation method and application

Abstract

The invention discloses a preparation method of a MnS three-dimensional nano array electrode material through MOF derivation in-situ synthesis. The preparation method comprises the following steps: dissolving terephthalic acid, manganese acetate and melamine in a water / DMF (N, N-dimethylformamide) mixed solution, and then putting the solution into a reaction kettle for hydrothermal reaction to prepare a manganese-based metal MOF precursor; and carrying out thermal treatment activation on the obtained precursor solid powder at 240 DEG C to expose open metal sites, then blending with thioacetamide, putting into the reaction kettle, and carrying out hydrothermal reaction again to obtain the final active positive electrode material. The preparation method is simple, no surfactant or template agent needs to be added, and the preparation process is simple and convenient.

Description

Technical Field

[0001] The present invention relates to the field of preparation of aqueous zinc ion battery electrode materials, and in particular to a method for preparing a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material. Background Art

[0002] The large-scale and rapid consumption of traditional resources by modern society and industrial systems has led to the risk of their depletion. The development of new renewable energy sources such as wind power and solar energy is the key to solving this problem. However, new energy sources are unstable and intermittent, so it is necessary to develop energy storage systems with excellent performance and reliability. Aqueous secondary batteries have the advantages of low cost, high safety, rapid ion migration, high capacity and long life, and are an excellent solution to the current energy storage problem. However, this battery is difficult to be widely used due to the limitations of large electrode volume expansion, structural deformation and poor rate performance. In this case, it is imperative to design and prepare composite electrode materials with suitable structures.

[0003] Transition metal sulfides are considered to be extremely promising cathode materials for aqueous zinc ion batteries (AZIBs) due to their high capacity and redox potential. The electrochemical properties of transition metal sulfides are better than those of the corresponding oxides, with higher capacity and redox potential, and are considered to be extremely promising cathode materials for aqueous secondary batteries. Energy storage devices based on transition metal sulfides also show higher energy density and power density, so they have become the current research focus. In previous studies, metal sulfides such as cobalt sulfide, nickel sulfide, molybdenum sulfide, and manganese sulfide have been widely reported. Among them, manganese sulfide (MnS) is considered to be a very promising electrode material for aqueous ion batteries due to its high theoretical specific capacity. However, the low actual capacitance and conductivity hinder the practical application of MnS. Therefore, it is urgent to develop an in-situ derivatization process method to make the manganese sulfide electrode material have good morphology and reasonable nanostructure, so as to construct high-performance aqueous ion battery devices. Summary of the invention

[0004] In order to overcome the defects in the prior art, the present invention provides an in-situ derivatization process method to prepare a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material with good morphology and reasonable nanostructure. The material can be designed and regulated from aspects such as particle size, heteroatom doping, metal species anchoring, micromorphology and composite structure to achieve the purpose of improving its electrochemical performance. The preparation method is based on a simple MOF precursor sulfurization in-situ derivatization method for preparing transition metal sulfides. First, a manganese-based MOF precursor is prepared by hydrothermal reaction of terephthalic acid, a certain proportion of manganese acetate and melamine, and then a final MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material is obtained through heat treatment and sulfurization treatment. The electrode material obtained by the present invention has a three-dimensional nanoarray structure. When the electrode material is used in an aqueous zinc ion battery, the aqueous zinc ion battery has a high electrochemical performance at 2 mA·cm -2 The discharge capacity at the current density reached 0.72 mAh cm -2 , at 20 mA cm -2 The discharge capacity is maintained at 0.51 mAh cm at the current density -2 , the capacity retention rate is 89.7% after 1000 charge and discharge cycles.

[0005] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0006] The present invention provides a method for preparing a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material, comprising the following steps:

[0007] Step 1: dissolving manganese acetate and melamine in a molar ratio of 2:1 to 10:1 in 40 ml of a water / DMF mixed solution, and forming a mixed solution after ultrasonic dispersion and magnetic stirring;

[0008] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reaction kettle, and reacted at a constant temperature of 100-160° C. for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0009] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6 -MOF solid powder. The obtained solid powder is heat-treated and activated at 240°C to expose open metal sites;

[0010] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6-MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0011] The MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material obtained by the above preparation method has a unique three-dimensional nanoparticle array structure. When the electrode material is used in an aqueous zinc ion battery, the aqueous zinc ion battery has a high conductivity at 2 mA·g -1 After 1000 cycles at a current density of 2 mA g -1 The discharge capacity at the current density is 0.72 mAh cm -2 , at 20mA·g -1 The discharge capacity is maintained at 0.51 mAh cm at high current density. -2 .

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) The present invention provides a preparation method and application of a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material. The preparation method successfully prepares a MnS nanoactive material with a three-dimensional nanoarray structure. Melamine is selected as an organic ligand, and self-assembles with metal manganese ions through coordination bonds to form a MOF precursor with intramolecular pores. At the same time, it can also promote the thermal catalytic reduction of metal ions in MOF, help the in-situ growth of active metal nanoparticles, and realize the controllable preparation of multi-level nitrogen-doped compounds. The prepared high-purity MnS nanoactive material provides a high specific surface area and abundant redox active sites, has better adsorption capacity for zinc ions and protons in the electrolyte, and has highly reversible ion and proton insertion / extraction behavior, thereby improving the specific capacity and cycle stability of the electrode material. When matched with the treated Zn electrode to construct an aqueous zinc ion battery, it exhibits high discharge capacity and good cycle stability.

[0014] (2) The preparation method adjusts the performance of the electrode material by controlling the concentration ratio of melamine and manganese ions in the MOF precursor. Experiments show that the electrode material obtained by the preparation method of the present invention can be effectively used in aqueous zinc ion batteries. The aqueous zinc ion battery has a high conductivity at 2 mA·g -1 The discharge capacity at the current density reached 0.72 mAh g -1 , at 20mA·g -1 The discharge capacity is maintained at 0.51 mAh g -1 , the capacity retention rate can reach 89.7% after 1000 cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a scanning electron microscope image of the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material prepared in Example 1 of the present invention.

[0016] Figure 2 This is an X-ray diffraction image of the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material prepared in Example 1 of the present invention.

[0017] Figure 3 This is the constant current charge and discharge curve of the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material prepared in Example 1 of the present invention in an aqueous zinc ion battery.

[0018] Figure 4 This is the long cycle curve of the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material prepared in Example 1 of the present invention in an aqueous zinc ion battery. DETAILED DESCRIPTION

[0019] The embodiments of the present invention will be described in detail below in conjunction with examples. It is necessary to point out that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above-mentioned content of the present invention.

[0020] Example 1: This example provides a method for preparing a MOF-derived in-situ synthesized MnS electrode material, the preparation method comprising the following steps:

[0021] Step 1: 0.268 g of manganese acetate (1 mmol) was dissolved in 40 ml of a water / DMF mixed solution, ultrasonicated for 10 min, stirred continuously for 10 min, then 0.025 g of melamine (0.2 mmol) was added, and magnetically stirred for 30 min;

[0022] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reaction kettle, and reacted at a constant temperature of 100-160° C. for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0023] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6-MOF solid powder. The obtained solid powder is heat-treated and activated at 240°C to expose open metal sites;

[0024] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6 -MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0025] The electrochemical performance of the MOF-derived in-situ synthesized MnS electrode material obtained in this example was tested using a double electrode system: -1 At this current density, the discharge capacity is 0.72 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.51 mAh cm -2 , at 2 mA g -1 After 1000 cycles under current density conditions, the capacitance retention rate is 89.7%.

[0026] Example 2: This example provides a method for preparing a MOF-derived in-situ synthesized MnS electrode material, the preparation method comprising the following steps:

[0027] Step 1: 0.268 g of manganese acetate (1 mmol) was dissolved in 40 ml of a water / DMF mixed solution, ultrasonicated for 10 min, stirred continuously for 10 min, then 0.013 g of melamine (0.1 mmol) was added, and magnetically stirred for 30 min;

[0028] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reactor, and reacted at 120°C for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0029] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6 -MOF solid powder. The obtained solid powder is heat-treated and activated at 240°C to expose open metal sites;

[0030] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6-MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0031] The electrochemical performance of the MOF-derived in-situ synthesized MnS electrode material obtained in this example was tested using a double electrode system: -1 At this current density, the discharge capacity is 0.56 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.37 mAh cm -2 , at 2 mA g -1 After 1000 cycles under current density conditions, the capacitance retention rate is 85.5%.

[0032] Example 3: This example provides a method for preparing a MOF-derived in-situ synthesized MnS electrode material, the preparation method comprising the following steps:

[0033] Step 1: 0.268 g of manganese acetate (1 mmol) was dissolved in 40 ml of a water / DMF mixed solution, ultrasonicated for 10 min, stirred continuously for 10 min, then 0.063 g of melamine (0.5 mmol) was added, and magnetically stirred for 30 min;

[0034] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reactor, and reacted at 120°C for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0035] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6 -MOF solid powder. The obtained solid powder is activated by heat treatment at 240°C to expose open metal sites;

[0036] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6 -MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0037] The electrochemical performance of the MOF-derived in-situ synthesized MnS electrode material obtained in this example was tested using a double electrode system: -1 At this current density, the discharge capacity is 0.49 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.31 mAh cm -2 , at 2 mA g -1 After 1000 cycles under current density conditions, the capacitance retention rate is 68.2%.

[0038] Example 4: This example provides a method for preparing a MOF-derived in-situ synthesized MnS electrode material, the preparation method comprising the following steps:

[0039] Step 1: 0.268 g of manganese acetate (1 mmol) was dissolved in 40 ml of a water / DMF mixed solution, ultrasonicated for 10 min, stirred continuously for 10 min, then 0.025 g of melamine (0.2 mmol) was added, and magnetically stirred for 30 min;

[0040] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reactor, and reacted at 100°C for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0041] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6 -MOF solid powder. The obtained solid powder is activated by heat treatment at 240°C to expose open metal sites;

[0042] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6 -MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0043] The electrochemical performance of the MOF-derived in-situ synthesized MnS electrode material obtained in this example was tested using a double electrode system: -1 At this current density, the discharge capacity is 0.44 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.27 mAh cm -2 , at 2 mA g -1After 1000 cycles under current density conditions, the capacitance retention rate is 50.5%.

[0044] Example 5: This example provides a method for preparing a MOF-derived in-situ synthesized MnS electrode material, the preparation method comprising the following steps:

[0045] Step 1: 0.268 g of manganese acetate (1 mmol) was dissolved in 40 ml of a water / DMF mixed solution, ultrasonicated for 10 min, stirred continuously for 10 min, then 0.025 g of melamine (0.2 mmol) was added, and magnetically stirred for 30 min;

[0046] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reactor, and reacted at 140°C for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0047] Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, washed repeatedly with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C 3 N 6 -MOF solid powder. The obtained solid powder is heat-treated and activated at 240°C to expose open metal sites;

[0048] Step 4: Mix Mn-C with a mass ratio of 8:1 3 N 6 -MOF solid powder and thioacetamide were placed in a beaker, 40 mL of deionized water was added, and the mixture was transferred to a polytetrafluoroethylene inner cylinder after stirring evenly. The reactor was placed in an oven, and the reaction temperature was set to 120 °C. After constant temperature reaction for 6 hours, the reactor was taken out, washed with deionized water, and then placed in an oven to dry for 6 hours to obtain the electrode material.

[0049] The electrochemical performance of the MOF-derived in-situ synthesized MnS electrode material obtained in this example was tested using a double electrode system: -1 At this current density, the discharge capacity is 0.52 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.39 mAh cm -2 , at 2 mA g -1 After 1000 cycles under current density conditions, the capacitance retention rate is 54.1%.

[0050] Comparative Example 1: This comparative example provides a method for preparing a MnS electrode material, the preparation method comprising the following steps:

[0051] Step 1: Mix 0.245 g of manganese acetate tetrahydrate and 0.075 g of thioacetamide in a beaker, add 40 ml of deionized water, and stir magnetically for 30 min after ultrasonication;

[0052] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then placed in a reaction kettle, and reacted at a constant temperature of 120° C. for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0053] Step 3: The powder crystals obtained by the reaction were centrifugally filtered, repeatedly washed with deionized water, and then dried at 60° C. for 6 hours to obtain MnS solid powder for preparing electrode materials.

[0054] The electrochemical performance of the MnS electrode material obtained in this comparative example was tested using a double electrode system: at 2 mA g -1 At this current density, the discharge capacity is 0.35 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.21 mAh cm -2 , at 2 mA g -1 After 1000 cycles under current density conditions, the capacitance retention rate is 67.3%.

[0055] Comparative Example 2: This embodiment provides a method for preparing a melamine-doped MnS electrode material, the preparation method comprising the following steps:

[0056] Step 1: 0.245 g of manganese acetate tetrahydrate, 0.126 g of melamine and 0.075 g of thioacetamide were mixed in a beaker, 40 ml of deionized water was added, and the mixture was magnetically stirred for 30 min after ultrasonication;

[0057] Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then placed in a reaction kettle, and reacted at a constant temperature of 120° C. for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed;

[0058] Step 3: The powder crystals obtained by the reaction are centrifuged and filtered, and repeatedly washed with deionized water, and then dried at 60° C. for 6 hours to obtain melamine-doped MnS solid powder for preparing electrode materials.

[0059] The electrochemical performance of the melamine-doped MnS electrode material obtained in this comparative example was tested using a double electrode system: at 2 mA g -1 At this current density, the discharge capacity is 0.27 mAh cm -2 , at 20mA·g -1 At this current density, the discharge capacity is 0.18 mAh cm -2 , at 2 mA g-1 After 1000 cycles under current density conditions, the capacitance retention rate is 70.5%.

[0060] It can be seen from the electrochemical performance test results of the above-mentioned embodiments that, in the entire MOF-derived in-situ synthesis method for preparing MnS electrode materials, the amount ratio of manganese acetate and melamine added has a decisive influence on the electrochemical properties of the composite material finally obtained, so it is necessary to control the concentration parameter within an appropriate range and execute it according to the scheme of the present invention to finally prepare a positive electrode material with electrochemical properties that meet the requirements of the present invention.

[0061] Although the present invention has been illustrated and described with specific embodiments, it will be appreciated that many other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended to include all such changes and modifications within the scope of the present invention in the appended claims.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material, characterized in that: The steps include: Step 1: dissolving manganese acetate and melamine in a molar ratio of 2:1 to 10:1 in 40 ml of a water / DMF mixed solution, and forming a mixed solution after ultrasonic dispersion and magnetic stirring; Step 2: The mixed solution obtained in step 1 is transferred to a polytetrafluoroethylene inner cylinder, and then transferred to a reactor, and reacted at a constant temperature of 100-140° C. for 12 hours, then taken out, and naturally cooled to room temperature after the reaction is completed; Step 3: The powder crystals obtained by the reaction were centrifuged and filtered, and repeatedly washed with deionized water, and then dried at 60°C for 6 hours to obtain Mn-C3N6-MOF solid powder; the obtained solid powder was heat-treated and activated at 240°C to expose open metal sites; Step 4: Put the Mn-C3N6-MOF solid powder and thioacetamide in a mass ratio of 8:1 into a beaker, add 40 mL of deionized water, stir evenly and transfer to a polytetrafluoroethylene inner cylinder, place the reactor in an oven, set the reaction temperature to 120°C, and react at a constant temperature for 6 hours before taking it out. After washing with deionized water, put it in an oven and dry it for 6 hours to obtain the electrode material.

2. The method for preparing the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material according to claim 1, characterized in that: The molar ratio of manganese acetate to melamine in step 1 is 5:1; the isothermal reaction temperature in step 2 is 120° C., and the reaction time is 8 hours.

3. The method for preparing a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode according to claim 1, characterized in that: The molar ratio of manganese acetate to melamine in step 1 is 10:1; the hydrothermal reaction temperature in step 2 is 120° C., and the reaction time is 8 hours.

4. The method for preparing a MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode according to claim 1, characterized in that: The molar ratio of the manganese acetate to melamine is 2:1; the hydrothermal reaction temperature is 120° C., and the reaction time is 8 hours.

5. The method for preparing the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material according to claim 1, characterized in that: The MnS particle size in the electrode material is 40-200 nm.

6. A MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material, characterized in that: The material is prepared by the molar ratio of manganese acetate and melamine as claimed in any one of claims 1 to 4. In step 2, the constant temperature reaction temperature is set to 100° C. and the reaction is carried out at this temperature for 12 hours.

7. An application of the MOF-derived in-situ synthesized MnS three-dimensional nanoarray electrode material as claimed in claim 1, characterized in that: The electrode material is applied to assemble an aqueous zinc ion secondary battery, the treated pure zinc electrode is used as the negative electrode, the electrode based on the prepared electrode material is used as the positive electrode, and a 6M KOH aqueous solution is used as the electrolyte; the positive electrode and the negative electrode are assembled into an aqueous zinc ion battery.

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